Equipment mounting apparatus is widely used in the Electronics and Communication Industry to mount plug-in circuit boards which are interconnected by backplanes of the equipment mounting apparatus to form composite electronic and communication systems. Typically, a backplane has a row and column configuration of terminal pins with each pin having a center section for mounting the pin in a hole of the backplane. One end of a terminal pin may be coupled with interconnecting cables and circuitry of the backplane and the opposite end may be engaged with connectors mounted on plug-in circuit boards. Insertion of circuit boards into the equipment mounting apparatus engages the connectors with the terminal pins to establish electrical connections between the circuit boards and interconnecting cables and backplane circuitry. Oftentimes it is necessary to short together ones of the terminal pins on the backplane when a circuit board is removed to protect apparatus of other circuit boards and to provide a closed loop on lines of electronic and communication systems.
Switch apparatus has been developed for use in shorting backplane terminal pins together. In one arrangement an inverted U-shaped member has one leg affixed to one terminal pin with the other leg normally in contact with another terminal pin. Other switch apparatus has a shroud member which is inserted over a group of terminal pins such that a U-shaped member positioned in a side wall of the shroud has both legs bent over to engage the terminal pins. In operation the edge of an insulating housing of a connector being inserted onto the terminal pins engages the U-shaped members and moves them aside to disengage them from the terminal pins. A problem with these designs is that on multi row and column connectors the switch apparatus can only be used with peripheral terminal pins engaged with the connector and cannot be used with center terminal pins in order to prevent damage to the pins and switch apparatus.
In yet another arrangement, switch apparatus for shorting a pair of terminal pins has a spring member affixed to one terminal pin and is configured and extended therefrom to engage a contact affixed to another terminal pin. Another program arises with this and the aforementioned switch apparatus in that backplane terminal pins are sometimes misaligned and result in the U-members and contacts failing to engage the terminal pins.
The foregoing and other problems are solved and a technical advance is achieved by apparatus arranged to short together and compensate for misaligned terminal pins of equipment mounting apparatus backplanes.